I had success with pstpassword 1.12 recovering my lost password on an Outlook 2007 .pst file!
How I got in this situation in the first place: My backup program was generating errors related to an Outlook email archive, so my system admin advised me to close the archive to try to resolve the problem. Oops! I didn't think to reset the password on the pst file before closing it.
With a company policy that requires changing passwords every few months and at least one upper case, lower case number and special character, and being admonished, don't write down your passwords, the odds of me remembering the password on an email archive I created over a year ago were slim and none. So there I was stuck with all my 2010 emails through July locked just out of reach.
I went looking online for a freeware password recovery tool for Outlook and found plenty of commercial offers and dubious looking claims, but pstpassword 1.12 from nirsoft.com seemed to stand out from the noise. After extensive searching, I couldn't find anything really bad about it. There were some discussion on a PCReview forum in the UK about it being tagged as a false Trojan. The discussion made sense to me, so I downloaded it (on my home PC). I made a copy of the .pst file on my portable USB drive and was able to run pstpassword against it (after extensive scanning the download with antimalware and antivirus programs).
It quickly gave me three passwords to try against the file. The first one looked like part of an old password that I might have used, but didn't work. The 2nd didn't work at all, but the third opened it right up. I copied the emails out of the old archive to a new one and I'm back in business. And now that I know how easy it is to crack the passwords on an email archive. Don't think you can hide something in there that you don't want found out!
So I'm satisfied. I wanted to document this so hopefully people will find it assuring that a real person found pstpassword 1.12 performed as described for me.